This invention relates to a drive system for a multi-mode reproducing apparatus preferably of the electrostatographic type. The drive system includes means for selectively driving sub-systems of the apparatus at a plurality of speeds.
A variety of electrostatographic reproducing machines are commercially employed which have different modes of operation. One type of machine utilizes a moving original exposure system wherein an original document is moved past a fixed slit optical system for projecting an image onto a moving photoconductive surface. These machines include a means for changing the magnification of the projected image and the speed of the moving original to provide reduction copies. Exemplary of patents in this area is U.S. Pat. No. 3,076,392 to Cerasani et al.
Other machines have been adapted to copy stationary original documents at a variety of magnifications or reductions through the use of a scanning optical system with different scanning speeds. Exemplary of patents in this area are U.S. Pat. Nos. 3,476,478 to Rees, Jr.; 3,542,467 to Ferguson; U.S. Pat. No. 3,614,222 to Post; and 3,837,743 to Amemiya.
The aforenoted machines are adapted to provide one or more modes of copying having different magnifications. Other forms of multi-mode copiers are available commercially. For example, in the Xerox 3100 LDC machine an optical system is provided which enables the machine to copy from a stationary original in a first scanning mode or from a moving original in a second fixed optical mode. This latter mode is particularly adapted for copying documents larger than the conventional viewing platen size. U.S. Pat. No. 3,877,804 to Hoppner is illustrative of a machine similar in many respects to the 3100 LDC machine.
Reproducing apparatuses including the capability of making copies from both moving and stationary originals are also described in U.S. Pat. No. 3,833,296 to Vola, and in IBM Technical Disclosure Bulletin, Vol. 12, No. 1, at page 173, June 1969.
It has been found desirable, in accordance with the present invention, to provide a multi-mode reproducing apparatus having the unique features of the 3100 LDC machine, including its extremely compact size, but also having the capability of reduction copying.
One area of interest in accordance with the present invention is the speed changing mechanism for changing the speed at which the scanning optical system is moved past a fixed optical system. The various patents alluded to about have employed a variety of speed changing mechanisms. Yet another approach to a variable speed control system for a variable magnification copying machine is described in Japanese laid open patent publication No. 84239/1973 which was laid open for public inspection Oct. 13, 1973. The system described therein comprises a source of drive input to an epicyclic gearing for causing a revolution of a planet gear, and a source of drive input for rotating a sun gear, and means for selectively connecting these sources with the epicyclic gearing. The epicyclic gearing has an output shaft for driving a movable reflecting mirror of the scanning optical system.
A variety of patents have issued on variable speed drive mechanisms. In U.S. Pat. Nos. 731,474; 731,472; 1,394,125; and 2,727,602; a variety of apparatuses are shown wherein a plurality of input gears are arranged about a common shaft in engagement with corresponding output gears arranged about an output shaft. One of the gear pairs is selectively engaged by a suitable mechanism in order to control the speed of the output shaft.
U.S. Pat. No. 2,975,648 to Doerres shows the use of electrically controllable spring clutches for a power transmitting device.
U.S. Pat. No. 3,220,275 to Hewes et al. shows the use of solenoid controlled spring clutches for a multi-speed power transmission. Spring loaded pawls acting on clutch detent collars provide normally disengaged clutches. The desired clutch is engaged to transmit power by a solenoid which is actuated to withdraw the pawl from the clutch detent collar.
Another area of interest in accordance with the present invention involves mechanisms for automatically returning a multi-mode reproducing machine to a desired base mode of operation after a copying operation in a different mode has ended. One approach to such a mechanism is described in U.S. Pat. No. 3,779,642 to Ogawa et al. In that patent a device is provided for automatically returning an optical system to a "usual" magnification position when the main switch for the copier is turned off.